Merge PDF Online
Combine multiple PDF or JPG files into one document. Drag files, change order, download in 5 seconds. No registration, runs in your browser.
Drag and drop your image here or click to select
PDF · Max size: 100.0MB
What Is PDF Merging?
PDF merging combines multiple PDF documents into a single file while preserving page order, formatting, bookmarks, and hyperlinks. It's essential for assembling multi-part contracts, preparing document packages for submission, or creating unified reports from separate files. Convertilo uses the pdf-lib library to merge without re-rendering — the original quality of text, fonts, and images is fully preserved. All processing runs locally in your browser.
About PDF Merging
Combining long reports and scattered scans into a single PDF keeps your paperwork tidy. Our merger runs offline in the browser, so the original formatting and metadata stay untouched.
How the merger works
- Sequential page stitching that respects the order you set
- Direct page copying without recompression or layout shifts
- Integrity checks for corrupted pages before they are appended
- Local processing that never uploads confidential documents
Technology Behind Our PDF Tools
Our PDF tools are built on two powerful JavaScript libraries that run entirely in your browser:
pdf-lib — A library for creating and modifying PDF documents. Used for merging, splitting, and page manipulation operations.
PDF.js — Mozilla's PDF rendering engine for parsing and displaying PDF content. Powers our PDF viewer and page export features.
Canvas API — Browser's built-in rendering API used for converting PDF pages to image formats (JPG, PNG, WebP) at any resolution.
All operations are performed locally — your documents are never uploaded to any server, ensuring complete confidentiality.
Why our PDF merger stands out
Manual order control
Drag files up or down and the merger stitches pages in the exact sequence you choose.
Preserved metadata
Page sizes, links, and bookmarks pass through untouched, so the final file behaves like the originals.
On-device privacy
Merging happens locally, which means contracts, invoices, and NDAs never leave your laptop.
PDF merge FAQs
Can I change the page order before merging?
Yes. Rearrange files in the list and the merged PDF will follow the updated sequence automatically.
Is there a size or page limit?
Each document can be up to 100 MB. There is no fixed page limit, although very large files may require a few extra seconds to finish.
Does the merger remove duplicate pages?
No. The merger copies your documents exactly as provided. If you add the same file twice it will appear twice in the final PDF.
Are my documents uploaded anywhere?
No. Merging happens entirely in the browser, so nothing is sent to external servers.